A method in which containers are sterilized in an inverted posture by using an aqueous solution of peracetic acid has been widely used for sterilizing bottles in an aseptic filling system. This sterilization method generally employs a procedure in which a bottle is held in an inverted posture, a spraying nozzle is inserted into the bottle mouth, and a sterilizing fluid is sprayed at least as a straight stick-like flow on the inner surface of the bottle, but the sterilization effect of the inside of the container in this method depends on whether the sprayed sterilizing agent or washing water directly collides with the inner surface of the container or the inner surface of the container is wetted when the liquid flows down along the inner surface of the container after the collision with the surface. The resultant problem is that if the flow rate is decreased, then uniform wetting characteristic of the inner surface of the bottle is deteriorated and sterilization is incomplete. For this reason, a large quantity of sterilizing fluid has to be sprayed inside the container within the predetermined time. Furthermore, in the case of synthetic resin containers such as PET bottles, complex concave-convex shape, such as reinforcing ribs, are present on the bottom and body section to increase the rigidity of container. Therefore, a large quantity of sterilizing fluid has to be sprayed over a long period in order to wet uniformly the entire inner surface of the container, thereby hindering the transition to speedup of lines that has been urgently required in recent years. Furthermore, that a large quantity of sterilizing fluid is required causes waste of the sterilizing fluid and high cost. Moreover, in the washing process, the sterilizing fluid (sterilizing liquid) that has adhered to the inner surface of the container in the sterilization process has to be completely washed off. Accordingly, the washing water has to come into contact with the entire inner surface of the container, in the same manner as in the sterilizing process in order to wash off the sterilizing liquid, and there are the problems that are similar to that in the sterilizing process.
In order to solve the above-described problems, the inventors have suggested a method by which the contact ratio of a sterilizing fluid with the inner surface of a bottle is increased and sterilization is conducted with high efficiency in which a first spraying hole is formed in the center of a distal end section of a spraying nozzle that is to be inserted into the mouth of the inverted bottle and a second spraying hole is formed to be circumferentially opened below the first spraying hole, the liquid sprayed from the two spraying holes toward the bottom section of the container flows down, and part of the liquid is stirred and pushed up by the sterilizing fluid sprayed from the second spraying hole and scattered over the inner surface of the bottle (ref. Patent Document 1).
A method for washing and sterilizing containers according to which a nozzle having a section to collect liquid is disposed below a container mouth, a mist or liquid flow supplied from a spraying hole of the nozzle is brought into contact with a reflux flow, and the distal end of the mist or liquid flow that collides with the inner surface of the container is constantly oscillated over the inner surface of the bottom section of the container has also been suggested as a method for sterilizing or washing a container in which the container is held in an inverted posture and a nozzle is not inserted into the container (ref. Patent Document 2).
Patent Document 1:
                Japanese Patent Application Laid-open No. 2003-181404Patent Document 2:        Japanese Patent Application Laid-open No. 6-121974        